DESCRIPTION: (Applicant's Abstract) In general, adult human beings show an aversion to contact or commerce with an entity which has been in contact with an undesirable or unknown person. This phenomenon is called negative interpersonal contagion. These negative feelings motivate avoidance of entities that have previously contacted diseased persons or morally compromised persons. We have published evidence indicating that negative interpersonal contagion accounts for part of the general tendency to avoid indirect contact with people with AIDS. A muting of negative interpersonal contagion seems to be operative when drug abusers share needles. This study involves the explication of the nature of the negativity that is "transmitted" by contact. Through questionnaires, interviews and controlled manipulations in a laboratory setting, we will distinguish and evaluate three models that account for interpersonal contagion: 1. passage of a material essence, 2. passage of a spiritual essence, and 3. pure association. We believe that most people operate with more than one model, the salient model in any situation being determined by the nature of the source of negativity (e.g., a person with an illness versus a person with a moral taint) and by individual differences. The study will also examine why interpersonal contagion varies depending on the individual and situation. Accounts explored will include the model of contagion that is operative, general sensitivity to contagion and disgust, and the way people frame their experiences (the extent to which they think about or attend to moral/health risk issues in daily experience). Attempts to increase contagion sensitivity (e.g., in needle sharing by drug abusers) or to decrease it (e.g., in over-response to casual contact with AIDS) should be informed by a better understanding of the psychological representation of the nature of the contagious entity.